Security Basics mailing list archives
Re: Please help with this strangeness
From: JGrimshaw () ASAP com
Date: Thu, 15 Jan 2004 12:31:14 -0600
Hi Michael, I do not believe you have it quite right on the addressing description. There would have to be four addresses--maybe a /30. It is unlikely you were assigned just three addresses--at least, I have never seen it happen. Perhaps your IP addressing is 81.174.224.68-71 /30? You would then have the following: .68 subnet address .69 assignable .70 assignable .71 broadcast. .72 could begin a new block of /30 addresses with .72 being the broadcast belonging to someone else. (Hey, I am only guessing based on what you suggested). Likewise, the block before you would start with 64 and end with 67. It would seem that if .69 is sending out these pings, which you say is the router. There would appear to be something else going on, so I am guessing you have private addresses internally and they are being NATed? How is the router connected? I do not understand how the IP address of the router is connecting to anything other than a point-to-point (if my /30 suggestion is true, which it probably is not) with another IP in the same range. You have said the .70 is associated with another server that is not in use, so my guess is that the router is not connected to it. So I am not sure what to think about that--can you provide more details? Make up numbers if you like, or use x.x.x.x and depict subnets. If the router has this .69 address, I would expect then that everyone is being NATed to use that address to access the internet? Are you using NAT overload? If this is the case, you may wish to sniff the internal segment and see where the ICMPs are coming from--having an IDS on the outside will not determine the internal source IP address, just the NATed one. Michael Thompson <mike () thompsonmike co uk> 01/14/2004 09:03 PM Please respond to Michael Thompson <mike () thompsonmike co uk> To cc Subject Please help with this strangeness Hi Security-basics, I was going through all my security logs today and I noticed something a little odd, and wonderd if anyone could offer any insight? I am not that good at detailed security! I have a IPBlock assigned from my ISP, where 81.174.224.68 to 81.174.224.70. As I understand it, 68 is a broadcast address, 69 is assigned to the router, 70 is for a server, which I dont use at the present time. Now, in my snort logs, which is connected to the outside of the firewall I get the following logs.. [**] [1:483:2] ICMP PING CyberKit 2.2 Windows [**] [Classification: Misc activity] [Priority: 3] 01/15-02:49:35.625784 81.174.224.69 -> 81.174.224.70 ICMP TTL:111 TOS:0xA0 ID:45600 IpLen:20 DgmLen:92 Type:8 Code:0 ID:512 Seq:52213 ECHO [Xref => http://www.whitehats.com/info/IDS154] [**] [1:483:2] ICMP PING CyberKit 2.2 Windows [**] [Classification: Misc activity] [Priority: 3] 01/15-02:49:35.641759 81.174.224.69 -> 81.174.224.68 ICMP TTL:110 TOS:0xA0 ID:45598 IpLen:20 DgmLen:92 Type:8 Code:0 ID:512 Seq:51701 ECHO [Xref => http://www.whitehats.com/info/IDS154] [**] [1:483:2] ICMP PING CyberKit 2.2 Windows [**] [Classification: Misc activity] [Priority: 3] 01/15-02:49:35.642071 81.174.224.69 -> 81.174.224.70 ICMP TTL:110 TOS:0xA0 ID:45600 IpLen:20 DgmLen:92 Type:8 Code:0 ID:512 Seq:52213 ECHO [Xref => http://www.whitehats.com/info/IDS154] [**] [1:483:2] ICMP PING CyberKit 2.2 Windows [**] [Classification: Misc activity] [Priority: 3] 01/15-02:49:35.649566 81.174.224.69 -> 81.174.224.71 ICMP TTL:111 TOS:0xA0 ID:45601 IpLen:20 DgmLen:92 Type:8 Code:0 ID:512 Seq:52469 ECHO [Xref => http://www.whitehats.com/info/IDS154] [**] [1:483:2] ICMP PING CyberKit 2.2 Windows [**] [Classification: Misc activity] [Priority: 3] 01/15-02:49:35.665945 81.174.224.69 -> 81.174.224.71 ICMP TTL:110 TOS:0xA0 ID:45601 IpLen:20 DgmLen:92 Type:8 Code:0 ID:512 Seq:52469 ECHO [Xref => http://www.whitehats.com/info/IDS154] Now, I thought of welchia or one of its many variants, and all machines are clean, the DHCP records show only one machine on the network connected mostly, thats my machine. It's clean. What could be causing these broadcasts? Any one have any ideas? -- Best regards, Michael (mike () thompsonmike co uk) Join the American Non-Sequitur Society -- we don't make sense, but we do like pizza. http://www.thompsonmike.co.uk/ PGP KeyID := 0xA9547E32 'To see a world in a grain of sand And heaven in a wild flower To hold infinity in the palm of your hand And eternity in an hour' Using TheBat! Version 2.02.3 CE Running On Windows XP (2600, Service Pack 1) Sent From OneAndOne
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Current thread:
- Please help with this strangeness Michael Thompson (Jan 15)
- RE: Please help with this strangeness David Gillett (Jan 15)
- Re: Please help with this strangeness JGrimshaw (Jan 15)
- Re: **SPAM** Re: Please help with this strangeness Michael Thompson (Jan 16)
- RE: Please help with this strangeness Burton M. Strauss III (Jan 16)
- <Possible follow-ups>
- RE: Please help with this strangeness Shawn Jackson (Jan 15)
- Re[2]: Please help with this strangeness Michael Thompson (Jan 16)